Acid production, acid and bile resistance of lactobacillus strains isolated from traditional sourdoughs

The study of biochemical characteristics and metabolic activity of Lactobacilli is necessary for selecting strains to be used as starter cultures for bread production. In this study، biochemical characteristics، acidification and probiotic properties of Lactobacillus strains (Lactobacillus plantarum، L. curvatus، L. paralimentarius) isolated from traditional sourdoughs were evaluated. All three Lactobacillus strains showed growth at 15ºC and different levels of NaCl (2، 4، 6. 5%) and pH (4. 4، 9. 6). Lactobacillus plantarum was capable of growing at 45°C. The Lactobacillus strains had capacity to ferment a large spectrum of carbohydrates. Lactobacillus plantarum and Lactobacillus curvatus was able to ferment pentoses (xylose and arabinose). Lactobacillus curvatus and Lactobacillus paralimentarius did not ferment rhamnose. The lactobacillus strains showed a proper acidifying ability after 9 h of incubation at 30°C، with pH values between 4. 5 and 4. 9. The results showed that Lactobacillus plantarum and Lactobacillus paralimentarius have potential probiotic value according to acid and bile tolerance tests.